1. Field of the Invention
The present invention relates to an air shelter for an electrical equipment that prevents an electrical equipment such as a motor from being submerged at the time of flooding by heavy rain, flood, tsunami, and the like.
2. Description of the Related Art
The applicant was granted a patent on a submergence preventing structure of an equipment that can prevent submergence of the equipment and can escape generated heat and oil vapor from the equipment (Japanese Patent Publication No. 5951020).
In this patent, an opening (61) is provided only at a bottom surface portion and a lower side of a side surface portion of a sealed box (60), and hence an interior of the sealed box is constantly communicated with outside air and the generated heat and the oil vapor from the equipment such as a pump (20) can be escaped, and furthermore, an excellent effect is obtained in that, even if the sealed box (60) is submerged, an air reservoir is formed in the sealed box so that the equipment can be prevented from being submerged by arranging the equipment in a region to become the air reservoir.
However, when the air reservoir is formed in the sealed box, the air leaks out to the outside from the air reservoir through a conduit tube, which protects an electrical wire connecting the equipment and a power source, and an occurrence of a phenomenon in which the equipment is submerged is confirmed.
The applicant thereafter found out that a technique for preventing air in a case from leaking to the outside little by little from an external line cable including a cable sheath and an electrical wire by filling a gap between the cable sheath and the electrical wire with resin has been proposed in patent document 2 (Japanese Patent Publication No. 5760598), and conducted an experiment of filling the gap between the conduit tube and the electrical wire with resin.
The leakage of air can be prevented for a period of a certain extent by filling the gap with resin, but the air leakage occurs when the resin is degraded after elapse of a long period from when the gap is filled with resin, and furthermore, the air leakage occurs when the submerged depth is deep and a considerable water pressure is exerted on the resin portion thus breaking the resin and forming a gap from the water pressure even by a slight degradation of resin.